Internal-combustion engine.



To all it may concern:

UNITED sra'rns ar rrr OFFICE.

HARRY wnmnooann, or PLYMoUrH, AND some 31mins LISHMAN, or sALooMBn,

ENGLAND rrtrnnnan-comnusrron ENGINE.

Specification of Letters Patent. ,Paqte nted Apr. 30, 1912.

Application filed August 24, 1911. Serial No. 645,820.

Be it" known that we, HARRY -W111i).- nounnna subject of the King of Great Britain arid'lreland, residing at Melville, Compton-Park, Plymouth, in the county of Devon,

' England, and JOHN JAMES LISHMAN, a sub- 1 je'ct of the King of Great Britain and Ireland, and resident at Moult Tors', Salcombe,

'South Devon, England, have invented certain new and useful Improvements in and Relating to Internal-Combustion Engines,

' of which the following is a'specification.

This invention relates to internal combustion engines of the two-stroke cycle type and of the kind having a cylinder of two diameters, in which works a piston of two corresponding diameters, said piston being hollow-or trunk-shaped and sliding over a fixed inner sleeve arranged concentrically within the cylinder walls, the arrangement -being-such that one portion of the piston operates in the main working cylinder of the'engine, while'the other portion works in an annular chamber formed between the in 'ner fixed sleeve and the cylinder walls and .divides-the same into two compartments.

trically within the cylinder walls and form- The object of this invention is to incor porate in'the construction above referred to, an arrangement of conduits and valves which enables an order of functions to be employed permitting of amore rapid and economical utilization of the combustible gases, a more efiicient after-disposal of the same, the lowering of the maximum pres- 35 sure and temperature, reduced heat loss to the cylinder walls and the obtainment of \other advantages, including more sustained pressures resulting in a more even torque.

'- In-the accompanying drawings, Figure '1 is a side sectional elevation showingone form of engine constructed in accordance with our invention, the crank case being removed. 2 is a front elevation with the .1 crank case in position and; showing one cyl- 4 51 ing an annular chamber inwhich the piston s end B works. Ports H and H, communicate betweenthe' annular chamber and asecond chamber or conduit'A Communication is established between the annular.

chamber and the working cylinder 0 of the engine by the passage or conduit J, within which passage a check or non-return. valve K 18 situated, and the sparking plug or igniter N is preferably also disposed just within this passage, as shown in Fig. 1. The pipe leading from the carbureter or other source of fuel (not shown) is connected in any convenient manner to the passage or passages E (Fig. 2) leading into the inner fixed sleeveover which the piston slides, and communicating with the annular chamber by the ports E as shown in Fig. 11

M M M in Fig. 2 show some of a series of ports serving as a communication' between the engine cylinder and the exhaust port M, while B and l3 are oil-ducts which may be provided in the piston-head to enable the lubricant, when splash-lubrication is employed, to reach the cylinder walls, this action being assisted by the well formed between the rim B and the inside of the piston B. I

A illustrates an arrangement of springcontrolled or other rings to counteract any tendency which the compressed charge may have to leak from the annular chamber,

while 0 shows one of the ducts leading to the valve G.

In Fig. 2 of the drawings the crank casing is shown in section at P and in elevation at P while an external flywheel R is mounted upon oneend of the crankshaft Q, although an internal flywheel may be'employed if desired.

he operation of the engine is as follows :During its in-st-roke the piston creates a vacuum in the annular chamber G which vacuum, at the end of the pistons upward or in-stroke, suddenly draws into the annular chamber G a charge of explosive mixture on the piston end B passing the port E. On the pistons outward stroke which is also the power stroke of the working cylinder 0 it slightly compresses this charge, while atthe same timepiston displacementin the middle chamber C draws in through the valve G a charge of 'air or other neutral gasat short atmospheric presenging charge-the exhaust port M .being opened when in this position. The charge.

of explosive mixture transferred from-one chamber to the other and displacing the air or neutral gas in front of it, is not sufficientto fill the working cylinder as well, air only reaching the working cylinder while the exhaust port is open. On the return or compression stroke of the piston B the exhaust port is closed and the charge of explosive gas-now trapped in the ,middle chamber C is forced through and past the conduit. J and the non-return valve- K into the working cylinder against the'rising pressure of the air now trapped in the latter, and 'at or about the end of the return stroke the gas charge is ignited by the sparking plug N or by other effective or convenient means. The piston is then driven outward by the explosion and expansion of the explosive charge, assisted by the independent expansive fluld, consisting mainly of air which as mentioned above is trapped in the cylinder at the beginning of the compression stroke, the oxyen of the latter being available for assistlng combustion when'required, resulting in an odorless exhaust due to the fact that complete combustion is insured owing to the trapped air providing an excess of'oxygen. Moreover this trapped charge of air or inert as also absorbs some of the heat generated y the explosion of the working charge and consequently the maximum pressure is reduced while at the same time a more sustained and even pressure will result and consequent on the maximum-temperature also belng reduced less heat will be lost to the cylinder. During this outward or working stroke, the hereinbefore described functions are taking place with the result that at the end of ,the stroke and at the moment the exhaust port M is uncovered, air for-scavengingis forced into the working cylinder in consequence of the displacement brought about by an explosive charge bei'ng again "transferred to, and trapped in, thev middle chamber C in readiness for the -re-- turn or compression-stroke as liereinbefore described.

Governing of the engine may be effected.

by any of the .well known methods, [and when it is arranged to governon the throtf tle, economical working of the engine is obtained due to the fact that compression is.

practically constant, evenwhen the explosive charge is great-l reduced,'becauseat. or-

' about the instant w en com ressionbegins the whole of the space in which compression takes place is filled with gas, artly air and partly'explosive mixture, an this space'is-i proportion of the explosive charge to neg.

tral gas. The igniter N is prefera 1 dis"- posed where shown in'thecharging uct J where it is surrounded at the required moment by the explosive-mixture enabling cer tain and rapid ignition 'td-take place.

Although it has been: stated in. the-specification that a charge'ofrair' or other neutral gas is forced from the" :annularchamber C,

into the cylinder, in actualjpractice small traces ofexplosive char 'will remain in the valvepocket between t valves K. and G,

so that the chargeof airor' neutral gas will. in all probability not be pure, but will con 7 tain a very slight admixture of explosive gas. It is also obvious that while retaining the.

functions herein described, we may vary the construction and arrangement'of'the piston and other parts without departing from the spirit of this invention. y

. Having now described our invention'what we claim asfnevv and desire to secure by Letters Patent is I v ;1.An internal combustion engine'of the two-stroke cycle type, comprisln' a cyl-- inder having two portions'of di erent diameters, one of the portions servingas a.

work insaid two portiolis' oft-he"cy linder j res ectively, asleeve 7 arranged concentri-- ca' y within the cylinder and forming with" one of the ortionsfot thecylinder an an? nular cham which. divided into two separatecompartr'nents by one of'the two piston parts, means for. admitting an explosive mixture into one 'of-the compart-.

main workin cylinder, 9. piston having two parts of di erent diameters arranged toment's," means for: admitting an inert'gas into the other compartment, means'for con-- necting, the latter compartment with .the

main workingc'ylinder, and means. for connecting the two com a'rtments with each other ear the endo -thegoutward strok I h reby'th working of the'piston in' sai annular chamber causes a charge of inert gas contained in one of the compartments to be forced into the main'working cylinder f by-andin front of the charge of explosive substantially'as described.

"'2. An internal combus'tion engineer the two-stroke cycle "type, .QOIIIPfiSlli, a, cyl.-- indjer having two; por'tionsfi'af er 'mixture" admitted and compressed in the-f other compartment'of the annular -"chamber,

cut di ameters, one off'the-'portionsfserving as main workin cylinder, a'piston having two parts of] di; crept-diameters arranged to work in saidtwo portions of ;the cylinder;-

res ectively, a fs leeve'arrangedf concentfii- .ca'l y within the cyiinderia a ormiug1iv iflrf one? of the-portions ay-cyli der an; an' 1?! nular chamber 'hich is divided into two separate con'i imrtn'ients by one of the two piston parts, passages formed in the sleeve within the cylinder for the admission of an explosive mixture into one of the compartments, means for admitting an inert gas to the other coi'npartment, means for connectthe latter compartment with the main working cylinder, an additional chamber, and passages between the latter and the annular chamber whereby the working of the piston in the annular chamber causes a charge of inert contained in one of the compartments to he forced into the main working cylinder by and in front of the charge of explosive mixture admitted in the other compartment from which it is expelled into the inert gas compartment past the additional chamber and through the passages be ween. the latter and the annular chamber, 'iantialiy as described.

an internai combustion. engine of the two-stroke cycle type comprising a cylinder having two portions of different, diameters, of the portions serving as a main working c tinder, a piston having two parts of different diameters arranged to work in said two portions of the cylinder respectively, a sleeve arranged concentrically Within the cylinder forming with one of the portions of the cylinder an annular chamber which is divided into two separate compartments by one of the two 1 parts, passages in the sleeve within under for admit-ting an" explosive into one out the compartments said passages being provided near the inner stroke end of the piston part arranged to work in the portion of the cylinder which forms an annular chamber wlth thesleeve, a conduit leading to the other compartment,

a non-return valve for admitting an inert forced thence into the other compartment toward, the 'end'of the outward stroke, the inert gas being drawn into its compartment during the outward stroke of the piston and forced thence .into the main working cylinder by the compressed explosive mixture while the exhaust port is open, and the explosive mixture being forced from the inert gas compartment into the working cylinder while the exhaust port is closed, substantially as described. I.

In testimony whereof We have signed our names to this specification in the presence of two subscribing witnesses.

HARRY lVHIDBOURN-F. JOHN JAMES LISHMAN. .Vitnesses ARTHUR JOSEPH Fonsnnw, AR HIBALD VHARDING. 

